A solid oxide fuel cell (SOFC) is an electrochemical cell with an anode (fuel electrode) and a cathode (air electrode) separated by a dense ion conducting electrolyte, said cell operating at high temperatures (500-1000° C.). The function of an anode in the solid oxide fuel cell is to react electrochemically with the fuel, which may be hydrogen and hydrocarbons, while the cathode reacts with air or oxygen to produce electric current.
Reviewing a basic operation principle of the SOFC, the SOH: is an apparatus basically generating electricity by the oxidation reaction of hydrogen and carbon monoxide. In the anode layer and the cathode layer, the electrode reaction is performed on the basis of the following reactions.
The basic chemical reactions at the anode side of an SOFC is the oxidation of fuels, such as hydrogen gas and/or carbon monoxide, to generate electrons:H2+O2−→H2O+2e−  Anode:and/or CO+O2−→CO2+2e−
The reaction at the cathode side is the reduction of oxygen to oxygen ions:O2+4e−→2O2−  Cathode:
Therefore, the overall reaction of an SOFC becomes:H2+½O2→H2O  Overall:Or H2+CO+O2→H2O+CO2 
That is, oxygen reaches the electrolyte through the porous cathode layer and the oxygen ion generated by the reduction reaction of oxygen moves to the anode layer through the dense electrolyte layer and again reacts with hydrogen supplied to the porous anode layer, thereby generating water. In this case, electrons are generated in the anode layer and are consumed in the cathode layer. As a result, when two electrodes are connected to each other, electricity flows.
Electricity is generated by the foregoing reaction. In this case, the efficiency of the SOFC is determined, in part, by the electric potential between the anode and cathode.
Researchers have been actively studying SOFC to utilize the fuel cell's potential high energy-generation efficiency. Fuel cells have many potential applications such as supplying power for transportation vehicles, replacing steam turbines and power supply applications of all sorts.